RET and columnar cell hyperplasia of the breast: Most of the CCH associated with MNG and Hashimoto’s thyroiditis, believed to represent “reactive” or “physiologic” (non-neoplastic) CCH, is different from (pre)neoplastic CCH, typically found in familial MTC/MEN-2 syndromes [16], where surgery may be mandatory even before definitive malignant transformation in patients carrying “high-risk” genomic RET mutations.